The first crew crammed enough drama into two weeks to last the entire program. Aside from the repair, there were controversies regarding communications and the crew’s health. NASA’s public affairs chief clashed with the Office of Manned Space Flight over private communications—whether the American press should be excluded from air-to-ground discussions about operational and medical problems. The Office of Public Affairs feared that private conversations would harm relations with the press; OMSF believed that forbidding private communications could endanger the mission. While this matter was debated, crewmen struggled with the ergometer, Skylab’s principal means of exercise. They devised a satisfactory means of riding the machine, but not before the strenuous activity caused a misunderstanding about their health. In the last two weeks of operations, with the additional power from the released solar array, the astronauts completed most of their assigned tasks.
Since its earliest days, NASA had prided itself on the openness of its programs—in sharp contrast to the secrecy maintained by the Soviet Union. The agency kept newsmen abreast of missions with transcripts of air-to-ground transmissions and frequent briefings. The policy worked well until the late 1960s, when the press began complaining of a credibility gap. Several newspapers viewed a private conversation from Apollo 9 as a move away from NASA’s open policy; the Washington Post noted that space officials were debating “how much to tell the public about some of the more intimate details of space flight,” and the Houston Post argued that the public had a right to medical information about the astronauts. In March 1969 Administrator Thomas Paine reiterated his support for an open program with private communications limited to special medical situations or operational emergencies. Any private conversation would be summarized for the press. NASA followed an open policy for the remainder of Apollo, although Houston officials chafed at the restriction, preferring candid discussions with the astronauts over a private line.1
For Skylab, JSC proposed to modify agency practice, justifying the changes on the length and the peculiar medical requirements of the program. The proposal established private medical conversations on a daily basis. The flight surgeon would inform the press of any significant medical news, but the tapes would be neither released nor transcribed for the news media. Private programmatic communications were permitted “when a real operational need existed.” A public affairs officer would monitor any private communication of this nature and summarize substantive matters for the press. There were also provisions for weekly unmonitored calls between the astronauts and their families.2
OMSF endorsed the Houston plan, noting that doctor-patient relations were considered privileged since most people were unwilling to discuss their physical conditions openly, and the astronauts were “no exception to this generally accepted and widely known situation.” Although the press received medical information on public figures, the bulletins contained only those details considered appropriate for release; specifics were often withheld. Private communications would help NASA doctors ascertain important preliminary symptoms, complaints that nearly everyone—including astronauts—would ignore under ordinary circumstances. OMSF expressed dissatisfaction with the practice of paraphrasing private medical conversations, citing the Apollo 15 experience when NASA managers had wanted information on James Irwin’s irregular heartbeat,* but feared that adverse publicity would threaten the remaining missions. At certain times, private communication would benefit the program without depriving the public of its right to know.3
John Donnelly, assistant administrator for public affairs, moved quickly to head off any change in policy, informing Administrator James Fletcher in January 1973 that he and OMSF could not agree. Private conversations with families posed no problems, but Donnelly strongly opposed routine medical conferences on a private loop. “It seems to me the condition of the men in the machines is as much, if not more, of a news element than the condition of the machines—particularly on a mission like Skylab.” Donnelly doubted that private medical communications would encourage astronauts to report “freely and honestly their physical condition.” Pilots were in general reluctant to admit problems that might shorten a mission or make them more dependent on the ground. He personally doubted that a private line would improve communications and feared the point would cloud the real issue: “Should the agency abandon a successful and respected policy which has won world-wide acclaim …?”4
In March 1973 Fletcher adopted a compromise that allowed routine medical discussions over a private line. Conversations would not be paraphrased, but the flight surgeon would provide newsmen with summary bulletins. The administrator also approved private operational communications “in matters of extreme emergency.” The calls could be initiated by flight controllers or the crew and would be paraphrased for the press by the public affairs office.5
The new policy was tested less than a week after launch of the first crew. Pete Conrad shared the dislike of many Houston officials for the open policy. While acknowledging the public’s right to know about NASA decisions, he believed that discussions leading to such decisions should be private. Late on 28 May, Conrad asked for a private conversation the following morning, saying, “It’s not [garbled] any emergency right now.” Several NASA officials were roused from bed to discuss the commander’s request. Despite the protests of the public affairs office, Schneider approved a private loop. Donnelly wanted the crew reminded that a private communication required an emergency, but Deputy Administrator George Low turned down the suggestion.6
The private communication on the 29th widened the rift between OMSF and the public affairs office. Conrad began by apologizing for the difficulty he had experienced riding the bicycle ergometer (see pp. 284–86). From there, the conversation moved to other problems including the solar array, docking probe, and workshop temperatures. Conrad expressed surprise that the mission was going so well and reported the crew “in good shape.” When newsmen received a summary an hour later, they questioned whether an emergency had really existed. Donnelly publicly stated that the situation had not justified a private communication and that ground personnel had erred in arranging one. Privately, he sought to release the tape of the conversation and have Conrad formally reprimanded. Although neither action was carried out, Dale Myers agreed to have the capsule communicator in Mission Control ask the crew if an emergency existed before arranging another private communication.7
A second controversy that day concerned the information recorded on board and relayed to the ground at intervals. This material was called “channel B dump data” to distinguish it from live air-to-ground conversations over the primary channel. In February, Conrad had mistakenly told a press conference that newsmen would receive transcriptions, although the agency actually planned to treat the recordings as confidential. The matter was forgotten until the 29th when the availability of the tapes became an issue. At Donnelly’s insistence, Myers initially agreed to release all channel B data, but then excluded information on medical experiments: Houston’s doctors did not want sensitive medical data released to the public lest laymen draw erroneous conclusions. Donnelly appealed to Low, arguing for the release of all channel B material to allay a “climate of mistrust.” He cited a possible challenge under the Freedom of Information Act and concluded, “It is a bad idea to censor this type of material because it calls into question the completeness of everything else we put out.” Low honored the doctors’ request, however, pending a full discussion with Fletcher.8
On the 31st, the administrator rescinded the requirement that Mission Control question the crew about the seriousness of an operational problem, fearing that such questioning might inhibit the crew from raising matters of concern. In a press release Fletcher said, “We do not want to risk the safety of the flight by having the astronauts infer, from our questions, that they should not use the private communications loop when a real need might exist.” The wording reflected George Low’s view that “extreme operational emergencies” included any matter of “real concern” to the crew that could not be resolved over an open line. Fletcher also approved Myers’s refusal to release medical data on the channel B tapes; the practice was in keeping with NASA tradition and the information had been promised to the medical investigators on a proprietary basis.9
Fletcher’s press release clarified NASA policy, but did not settle the issue of private communications. Donnelly remained suspicious of his NASA associates and fearful of a credibility gap. After the launch of the second crew, he warned Fletcher that reporters for Time, the New York Times, and the Chicago Tribune were unhappy about deviations from the traditional open policy. These representatives were particularly concerned that the trend toward routine private conversations would weaken their negotiating position with the Soviet Union regarding communications for the Apollo-Soyuz flight. Donnelly’s aggressive defense of the newsmen’s interest may have affected his own credibility within NASA, because the press did not appear that concerned—at least not in print. Absorbed with Watergate, newspapers gave Skylab relatively little attention, and most coverage focused on the crews’ success; little was written about private communications.10
With one exception, Skylab crews avoided private operational conversations after 29 May, perhaps from fear of further controversy. Conrad, for one, believed the lack of a private line inhibited communications. After the mission he complained “that all too often he was left in the dark” concerning Houston’s plans. He cited, as an example, learning from his wife, during a birthday greeting, about EVA plans to free the solar array. He acknowledged that more information could pass over open lines, but thought that Houston officials would be more candid over a private channel. The lack of a private operational channel had little apparent adverse affect on the first two missions; on the last flight, however, the open policy would contribute to the poor communications between Houston and the crew. In the issue of private communications, the agency’s political interest ran counter to its operational needs, and no satisfactory compromise was achieved.11
NASA’s astronauts and doctors had disagreed about medical experiments since Gemini days. Astronauts felt they were being treated like guinea pigs in what were often viewed as unnecessary experiments. Mike Collins called the inflight sleep analysis experiment on Gemini 7 “a classic case of the tail wagging the dog, with decisions to be made by the wrong people (the medics) in the wrong place (the ground) with the wrong information (brain waves).” The medical directorate, on the other hand, viewed its experiments as a key element of manned spaceflight and insisted on rigid controls. Dr. Charles Berry acknowledged that most agency managers, as well as astronauts, considered his staff “over cautious”; but he believed the caution was justified. NASA was under substantial pressure from critics of manned spaceflight, and it was important to make sound judgments about the astronauts’ adjustment to space.12
Physical exercise was one of the activities disputed by the two groups. Doctors wanted to control exercise before and during a mission because of its medical implications; ideally they would measure all physical activity. Astronauts objected to rigid controls because of personal inconvenience, as well as a belief that they could best judge their need for exercise. The compromise worked out, for Skylab made no attempt to regulate all exercise; the medical office settled for periodic measurements of physical condition. Daily exercise was left to the individual astronauts, with the understanding that crew members would report how long and hard they had worked. The ergometer, the principal exercise machine, provided a means of gauging the workload.13
Kerwin in the lower-body negative-pressure experiment M092. Weitz is helping him attach sensors. The purpose of the experiment was to provide information concerning cardiovascular adaptation in space and impairment of physical capacity upon return to earth. SL2-2-180.
The first crew was allowed, by the flight plan, 30 minutes a day for exercise on either the ergometer or an isometric device. Twice a week each crewman tested his physiological response to exercise by performing the metabolic experiment, M171. More specifically, Ml71 measured the changes in metabolic response to work, charting blood pressure and heart rate as well as oxygen consumption.* There were five periods to the 25-minute test: a rest phase to establish the metabolic rate; three periods of exercise at 25%, 50%, and 75% of the crewman’s maximum capacity for work (determined in preflight tests); and a recovery phase. A secondary purpose of Ml71 was to evaluate the ergometer as an exerciser for long-duration flights. During the lunar missions, the crew’s ability to exercise had been limited by the size of the Apollo spacecraft, and most astronauts had shown a decline in physical conditioning. The loss was temporary (within 36 hours they normally returned to preflight levels of exercise), but it indicated a potential danger for long-term flight.14
Problems with the ergometer surfaced during Weitz’s first run of the metabolic experiment on 28 May. Because of the heat in the workshop, Kerwin had recommended shortening the schedule for M171. Houston encouraged the crew to attempt the entire exercise, since deviation would affect experiment controls. Midway through the third level of the exercise, however, Weitz called it quits. The waist and shoulder harness—intended to secure the astronaut to the bicycle—was restricting his movement. Weitz found that he was doing too much of the work with his hands, not enough with his big leg muscles.† During the private communication on the 29th, Conrad reported that the ergometer could not be ridden in space as it had been on earth and questioned whether the crew could finish the full regimen. A few hours later, Kerwin too failed to complete the exercise. Conrad persisted to the end but compared the third level to “20 minutes of a full workload.” He told Mission Control: “I was really running out of gas. And yet, I was using muscles that I don’t normally use on the ground.” The crew recommended lowering the workload (amount of resistance in the ergometer pedals) by 10–20% to compensate for the difficulty of riding in space.15
Conrad riding the ergometer as the experiment’s principal investigator had envisaged, above, SL2-8-714, and in his own zero-g adaptation, right. SL2-9-742.
The initial problems on the bicycle were aggravated by a tight schedule that reduced the crew’s physical exercise. On 31 May Kerwin complained that Houston’s flight plan was effectively eliminating the period of physical activity: “It’s been scheduled strictly on paper, as far as we’re concerned, because the other scheduled tasks have taken so much time that they have completely absorbed and wiped out PT [physical training].” Too often exercise was scheduled just before or after a major activity having a fixed time requirement. Kerwin considered this a serious mistake and hoped that Mission Control would give the exercise period “priority over most other objectives.”16
During the second week, the crew experimented with different positions on the ergometer, eventually discarding the harness altogether. The astronauts found that they could stabilize themselves by locking their triangular cleats into the pedals and placing their hands against the ceiling or on the handlebars. According to Weitz, it was “a revelation … it’s so much easier than strapping yourself down.” Conrad displayed a knack for “arm ergometry,” pedaling with his hands while his feet pressed against the ceiling. After discarding the harness, and after the workshop had cooled down, the crew returned to preflight levels of exercise. At a press conference on 6 June, Edward Michel, principal investigator for Ml71, acknowledged that elimination of the harness affected the controls for his experiment just as the first week’s excessive heat would have to be considered in assessing the initial runs. He seemed relieved, however, that the crew had found a way to ride the ergometer.17
On 4 June the crew began plans to free the solar array, confident that they had resolved their difficulties on the ergometer. Houston’s doctors were disturbed, however, by the initial results from the Ml71 experiment. Pulse rates had run abnormally high, and Conrad showed a series of heart palpitations.* The medical office had said nothing about the matter to the press or the crew; in fact, the doctors had not known the details for several days because of delays in the flow of data. They attributed the high rates to the heat and harness, but some thought they might be seeing early effects of weightlessness. The doctors were particularly anxious to retest Conrad before he attempted extravehicular activity. That evening Charles Ross, the crew’s physician, told Conrad about the problem and said that Houston was making special plans for his M171 run the next day, scheduling the experiment over North American tracking stations so that the medical office could receive the data quickly. The doctors recommended that Conrad reduce his maximum workload. If he showed further palpitations, the doctors wanted him to avoid strenuous exercise—including the extravehicular activity.18
Dr. Kerwin giving physical examination to the commander of the first crew. SL2-2-157.
The crew was taken aback, believing that the doctors had overreacted to outdated information. Conrad was particularly upset by Houston’s failure to ask Dr. Kerwin or himself for a personal evaluation. Before his M171 run on the 5th, Conrad requested a private communication to clarify the medical situation. Over the private line, the crew told Skylab officials that they were in excellent condition and wanted to exercise as much as possible. Kraft expressed regret at the apparent misunderstanding and assured the crew that there was no doubt about their good health. In fact the medical office had altered its plan since the previous evening, but had not told the crew. The new instructions left the Ml71 workload to the crew’s discretion.19
The matter was closed that afternoon when Conrad ran the full Ml71 protocol without difficulty. There were no attempts thereafter to play down the importance of exercise. Conrad would later describe the incident as “a very key thing in the whole flight.” At the end of the mission he was in better condition than his crewmates, presumably because of his higher level of exercise. At the first crew’s urging, Houston increased physical activity on later missions, with beneficial results.20
The astronauts found the first week’s schedule too demanding. On some tasks there was little difference between operating the trainer and the flight model; but other activities, such as handling small items or locating equipment in stowage, took much longer in zero gravity than expected. Although additional time had been allowed for them to become acclimated, the astronauts ran behind schedule (as would the later crews, at the start). The problem was compounded on the first mission by inex perience at Mission Control. Skylab operations represented a considerable change from Apollo, and coordination occasionally faltered during the first week.21
The men spent the first three days activating the hot workshop. They adjusted to space quite well, showing no sign of motion sickness, but found the pace fatiguing. When operations began on the 29th, the astronauts worked past dinner to complete their assignments. After a second hectic day, Conrad concluded that the schedule was unrealistic: “We were trying to do it all … and were getting inefficient by rushing.” He informed Mission Control that the crew was “running all over the spacecraft,” and that there were “enough guys down there to think out the flight plan a little better than you’re doing.” On the 31st Conrad offered a number of planning suggestions: allotting more time for housekeeping and individual experiments, scheduling one crewman to perform an entire procedure, and minimizing the loss of time between experiments.22
A holiday on 1 June gave the crew a chance to relax and catch up on housekeeping chores. During a 15-minute telecast, the astronauts performed acrobatic feats and their own “Skylab 500.” Conrad had wagered some Houston friends before launch that centrifugal force would allow him to overcome weightlessness and walk erect on the storage lockers that circled the upper deck of the workshop. Starting on their hands and knees in a slow crawl, they built up speed and moved to a crouch, then finally walked rapidly on the lockers. The television pictures provided the proof.23
Much of the second week was spent on freeing the solar wing. The full schedule of experiments was resumed on the 9th, following a day of housekeeping and relaxation. After the excitement of the first two weeks, normal operations seemed humdrum; Kerwin recalled one evening when “it seemed like it had been day 18 for a week.” As the astronauts adjusted to their surroundings, they frequently found themselves ahead of schedule. They decided not to ask for more work, however; preparations for the return to earth would take up much of the last week, and they did not want to set unrealistic standards for the next crew.24
Skylab’s first three weeks in space was a trying time for the principal investigators. For 10 days they faced the possible loss of years of work. After the crew’s launch, the shortage of electricity caused further anxiety, and many scientists viewed each day as the last chance to gather data. “The risk of the mission being cut short,” John Disher recalled, “was a big factor in the almost frantic approach of some … experimenters.” If anything, the problem was acerbated by the apparent quality of the science. The investigators were pleased with the initial data, but as Robert Parker, program scientist, put it, “They felt starved for it.” Few scientists thought they were getting their rightful share of the flight plan, and Parker (who had assumed responsibility for scheduling experiments just a few months earlier) did not enjoy their trust. Consequently, “most of them thought their experiment was the only one that had been reduced in scope.” Karl Henize, a scientist-astronaut and investigator for an experiment in stellar astronomy, recalled a feeling of frustration bordering on paranoia: “You never quite knew what the other man’s problems were, and you’d put in your requirements and you’d get them back all mangled…. everybody was mad at each other.”25
Kerwin strapped into his sleep restraint and wearing the instrumented cap for the sleep-monitoring experiment Ml33, which evaluated the quantity and quality of sleep during prolonged spaceflight. SL2-3-205.
The return of full electrical power did little to ease scheduling pressure. Investigators were anxious to make up the time lost in deploying the parasol and solar array—about 15% of the time allotted for science. At a news briefing on 8 June, Parker likened his problem to cramming a size 10 foot into a size 8 shoe: something had to give. Medical experiments retained their priority; during the last two weeks the crew actually increased the frequency of cardiovascular and metabolic tests. The earth-resource experiments, hard hit by the initial power shortage, were given a high priority, as were the solar observations. Conversely, the corollary experiments took a lower priority. Parker tried, however, to give everyone some time in the flight plan. By mission’s end on 22 June, the crew had reduced the shortfall of experiment hours, meeting nearly 100% of the medical requirements and 80% of the solar observations. Earth resources remained the hardest hit of the major experiments; because of the shortened runs during the first half of the mission, the crew conducted only 60% of the work programmed for that area.*26
Conrad and Weitz working with the materials-processing facility M512. SL2-9-738.
While most scientists expressed satisfaction with the results of the first mission, some investigators, according to Parker, “felt they had really gotten gypped.” The general mood was “that they had put an awful lot of their time and NASA’s money into getting very little data, and they’d better jolly well get more time … in the next mission.” During the next two missions, Parker sought to placate his colleagues with periodic planning sessions. The meetings proved helpful, allowing the investigators to gain an appreciation for each other’s problems. Even more helpful in alleviating discontent, however, was the steady stream of data from Skylab.27
With its various switches, monitors, and checklists, the console for the solar telescopes was a complicated station. After working with it some time, one astronaut concluded, “there’s no way to go very long … without making a mistake, you just hope that you don’t make any that are too large.” Kerwin acknowledged a lot of mistakes on the first mission, attributing most of them to frequent interruptions. “We never got to buckle down into the ATM routine up there, at least not for more than a few days at a time.”28
One of the biggest problems with the ATM console was its flare detection system. Designed to alert the crew if a solar flare developed while no one was at the console, it frequently went off as the workshop passed over the eastern part of South America, where the earth’s radiation belt dips much lower. The magnetic field triggered the flare alarm whenever the crew left the system running. Kerwin later recalled his frustrations with the detector: “Every time I left the alarm on, it wasn’t 5 minutes until the alarm sounded. Then somebody had to break loose from what he was doing, go up to the ATM console, and turn it off…. I never realized that [the South Atlantic anomaly] was so ubiquitous.” Allowing for exaggeration, the false alarms were a frequent disturbance which the crewmen put up with to catch a flare. Kerwin’s eagerness, in fact, proved an early embarrassment. On 30 May, reacting quickly to an alarm, he forgot that he was over the South Atlantic and started the procedure for recording a flare; fortunately he realized what had happened before he wasted much film. While Kerwin gracefully accepted the teasing about his mistake, the incident did not increase his enthusiasm for the alarm system. After the mission, he evaluated it as “absolutely worthless.”29
For three weeks, the first crew’s hopes for a flare went unfulfilled; then on 15 June persistence was rewarded. The astronauts had agreed to give up their free day to make up lost time on the experiments, but the outlook for solar activity was not promising. Houston reported a few subnormal flares and a possibility of more action, to which Kerwin responded: “We’d like some supernormal flares, please.” Five hours later the mission’s first good-sized flare was spotted. Kerwin told Houston: “I’d like … you to be the first to know that the pilot [Paul Weitz] is the proud father of a genuine flare.” The solar scientists were extremely pleased that Weitz had tracked the flare through two minutes of its rising portion and the subsequent fall, a task that involved monitoring several displays to confirm the solar activity, initiating several flare programs, and then pinpointing the flare with the solar telescopes—all within a matter of seconds.30
Any disappointment that the crew may have felt about its ATM work was not shared by the principal investigators. During the course of Skylab’s development, solar scientists had been, at times, among the program’s most vocal critics. Many noted astronomers questioned the wisdom—at least the cost—of manning solar telescopes in space (p. 81). This attitude changed dramatically as the results began arriving.31
The crew gave Skylab high marks in the postflight debriefings. With a few exceptions, experiment hardware worked satisfactorily. The multi-spectral scanner (one of the earth-resource instruments) caused Weitz much unhappiness. “Adjusting the focus completely messed up the alignment. More than once we lost the alignment completely. It just dropped off the bottom of the scale.” As a result, 3 of the 12 passes with the multispectral scanner were of marginal quality. All three crewmen complained about calibrating the body-mass measuring device. Each astronaut’s weight was determined daily by measuring the oscillatory frequency of a spring-mounted chair. Three times during the mission the device was calibrated, using objects of known mass; the problem was getting the items—in particular, several heavy batteries—to stay in place during the calibration. For the most part, however, hardware performance surpassed the crew’s expectations.32
The crew gave the support team many compliments. Weitz “could not say enough about the high-fidelity trainers,” and Kerwin noted that training personnel had even “put in the failures and the sticky parts.” Most checklists worked well, except for inflight changes; there was no easy way to catalog teleprinter messages for later reference. Conrad recommended that the next crew take notebooks and keep teleprinter messages in a permanent file. Channel B communications also needed improvement; when the astronauts replied to queries, their answers—sent down over the secondary channel—sometimes disappeared for days.33
If the astronauts were satisfied with Skylab as a home, they could not recommend it as a restaurant. Food seemed to lose its flavor; bread that had tasted “very good” in Houston was “very much different and … worse tasting” in space. Generally, the astronauts’ preferences remained the same. Weitz’s comment was typical: “The foods I liked I continued to like. The foods I didn’t like, my dislike for them increased.” One noticeable difference was the desire for spicy foods, which the astronauts attributed to their loss of taste and smell. (The crewmen’s senses were probably dulled by head congestion, a result of blood pooling in the upper regions of the body.) German potato salad, long on vinegar and onions, proved so popular that the crew used up all four cans on board. As for categories of food, the frozen foods were rated most acceptable and the reconstituted items the least satisfactory. Conrad recommended that the next crew take some spicier foods along and allow more time to reconstitute the dehydrated items. “I found that if I reconstituted the peas, the beans, and the asparagus early, and then reheated them, I still didn’t like them, but they were a lot easier to choke down than when I added the hot water, shook up the bag and then tried to get them down.”34
Alan L. Bean, commander of the second crew, on the body-mass measuring equipment of experiment M172. 73-H-974.
Conrad turns barber, Weitz holds a vacuum hose. Note how the food trays were attached to the sides of the small galley table. The much-debated wardroom window is in the background. SL2-9-755.
Matters were made worse by the astronauts’ rigid diet; with fixed menus, they knew when to expect the undesirable foods. The diets provided some variety, but not enough. Kerwin recalled that “foods that we did pick were not palatable to us when taken repeatedly, partly because we just didn’t eat that kind of food that often.” He recommended that future programs use a plan originally considered for Skylab, in which categories of food were defined and items within a category were interchangeable.35
Despite the shortcomings of the cuisine, the crew obviously enjoyed the flight. Where else could one perform such acrobatics or enjoy such a marvelous view? Moreover, the mission had been a huge success. Despite personal and mechanical problems, ground and flight crews had persevered. The last extravehicular activity provided a fitting climax. The primary goal had been to replace ATM film; as a secondary objective Houston wanted to try to reactivate one of the dead power modules on the electrical system (p. 258). After reviewing test results, Huntsville engineers had concluded that a relay was stuck and that a blow to the battery housing would free it. Following instructions sent up by teleprinter, Conrad jarred the housing smartly with a hammer, and within minutes electricity was flowing again.36
The medical experiments did not end with return to earth. Here Kerwin undergoes one more check aboard U.S.S. Ticonderoga, 22 June 1973. 73-H-544.
1. PREFLIGHT HISTORY HAS INDICATED PAST RELAY HANG-UPS WHICH HAVE BEEN FREED BY MECHANICALLY SHOCKING THE RELAY.
2. RECOMMENDED PROCEDURE IS TO STRIKE THE CBRM HOUSING AT THE POINT INDICATED BELOW. TESTS INDICATE THAT YOU CANNOT HIT THE CBRM HARD ENOUGH TO DAMAGE IT.
3. DIAGRAM BELOW IS DETAIL OF CBRM. LOCATION WRT CENTER WORK STATION IS SHOWN IN ATM SCHEMATICS BOOK, DIAGRAM 5.9, LOCATION L5.
5. CODE 
= ALLEN HEAD SCREWS ON RAISED PORTION OF CBRM.
= ALLEN HEAD SCREW ON WHICH TO POUND.
Teleprinter message sent to first Skylab crew, giving instructions for repair of charger-battery-regulator module during extravehicular activity.
* This occurred in lunar orbit, following three tiring days on the moon. NASA doctors later attributed the excessive fatigue to a low level of potassium.
* Many readers will recognize Ml71 as an aerobic exercise. Aerobic, “living in air,” in the last decade has taken on the additional meaning of physical activity that increases heart and respiratory activity for a sustained period of time.
† Caldwell Johnson had argued that the ergometer would not work in space and had provided an alternate design. Why it was rejected is not completely clear.
* In a press conference on 5 June, Dr. Royce Hawkins described Conrad’s condition as a premature ventricular contraction, but indicated that the condition was not uncommon.
* Understandably, NASA officials stressed the amount of work accomplished rather than the shortfall. The first crew took 29 000 pictures of the sun and 14 kilometers of magnetic tape for earth resources. See chap. 18 for a detailed treatment of results.
